1. Field of the Invention
The present invention relates to a tool/package that applies a consistent uniform layer of thermal grease to a top surface of an integrated circuit that is mounted to a printed circuit board.
2. Description of Related Art
Some integrated circuit packages contain a heat sink to facilitate removal of the heat generated by the circuits. To minimize the thermal impedance between the integrated circuit and the heat sink, it is desirable to mount the heat sink directly to the die. The surface roughness of the heat sink material may create a relatively high thermal impedance at the interface of the heat sink and the die. Thermal grease is typically applied to the surface of the integrated circuit to lower the thermal impedance of the die/heat sink interface. The thermal grease fills in the pits and asperities that reside in the surfaces of the heat sink and the integrated circuit to provide a direct thermal conductive path between the two package components. It is desirable to accurately control the thickness of the thermal grease. Too much thermal grease will increase the thermal impedance of the package. Too little thermal grease might not adequately fill the spaces between the heat sink and the integrated circuit. It would be desirable to provide a tool and resultant integrated circuit module that accurately control the thickness of thermal grease applied to an integrated circuit.
The present invention is a tool which accurately controls the thickness of a thermal grease applied to an integrated circuit that is mounted to a printed circuit board. The tool includes a bracket that supports the printed circuit board and the integrated circuit. A thermal grease is applied to the top surface of the integrated circuit. A lid is attached to the bracket to capture the printed circuit board. The lid has a platen that is separated from the integrated circuit by a space which has a predetermined thickness. The space defines the thickness of the thermal grease. Any excess thermal grease is pushed out of the space by the lid so that a consistent thickness of thermal grease is applied for each integrated circuit assembly. The bracket, lid, integrated circuit and printed circuit board can be mounted to a motherboard as a single integrated circuit module. Alternatively, the lid can be detached from the base so that the grease covered integrated circuit can be removed from the tool for subsequently assembly.